5. The Control of Vocalization in Birds

Abstract

The song ontogeny of birds is classified into 2 types. One kind of bird must learn the species-specific pattern of its song, the other need not learn but inherit the proper pattern. The former type of bird, for instance the canary has complicated vocal organ, the syrinx and the latter has a primitive syrinx. The peripheral and brain innervation patterns are also different between the two types of syrinx.
One cerebral vocalization center of the canary, either the n. robustus archistriatalis (RA) or the hyperstriatum ventrale, pars caudale (HVc), has a specific role in performance of the song and elicits a specific pattern of unit spike discharge. The neurons of the centers responsible for voluntary vocalization also respond to sound stimulation at the same time: the HVc responds to white noise, and the RA responds to clicks, pure tones and FM sounds. An interconnecting organization between the vocal and auditory, or motor and sensory systems, in the cerebrum is speculated to be a means of connecting the RA and thalamic organization of the auditory area.